1. Field of the Invention
The present invention relates to foaming cleaning compositions, and in particular to an in situ foaming cleaning composition incorporating a bleach and which is formulated to have utility as a drain cleaner, or as a hard surface cleaner.
2. Description of Related Art
Published Japanese applications to Ishimatsu et al JP 59-24798 and JP 60-32497; JP 59-164399, to Miyano et al, and Sakuma, JP 57-74379 all disclose, describe and claim a binary foaming cleaner having utility as a drain opener. None of these references, however, teach, suggest or disclose a thickened formulation, nor any of the advantages and foam characteristics associated therewith.
A hypochlorite composition paired with a chelating agent/builder solution in a dual chamber container is disclosed in U.S. Pat. No. 5,767,055 to Choy et al.
Drain cleaners of the art have been formulated with a variety of actives in an effort to remove the variety of materials which can cause clogging or restriction of drains. Such actives may include acids, bases, enzymes, solvents, reducing agents, oxidants and thioorganic compounds. Tobiason, U.S. Pat. No. 5,264,146, Steer, et al, U.S. Pat. No. 5,630,833 and Taylor, Jr. et al., U.S. Pat. No. 4,664,836 all disclose dry compounds which generate foam when mixed with water in a drain. Kuenn, U.S. Pat. No. 4,619,710 describes a dry in-sink garbage disposal cleaning composition which uses adipic acid and sodium bicarbonate to generate gas upon contact with water. This composition requires mechanical shearing from the disposal to assist in foam generation. Davis, U.S. Pat. No. 4,206,068 describes an exothermic drain opening composition comprising an oxidant and a reducing agent in a compartmentalized container.
In view of the prior art, there remains a need for a cleaning composition capable of generating foam and heat in-situ. There further remains a need for foam-generating, exothermic composition which provides both chemical and physical cleaning especially on non-horizontal surfaces.
It is another object of the present invention to provide a composition capable of forming an active-carrying foam in situ.
It is another object of the present invention to provide a composition capable of generating a stable foaming active cleaner.
It is another object of the present invention to provide a triple component composition and containment means which isolates each component during storage.
It is another object to provide a drain opening composition which is formulated to be safe to store and use.
It is another object of the present invention to provide a foaming cleaning composition having utility as a drain cleaner by virtue of its rheology.
It is yet another object of the present invention to provide an exothermic cleaning composition.
More specifically, the composition is a product of three liquids or reactants which are separately maintained prior to forming an admixture during delivery to a surface to be treated, whereupon the admixture generates a heated foam sufficient for cleaning efficacy and stability. A first liquid includes an oxidant, such as a hypohalite or a hypohalite generating agent (hereinafter xe2x80x9chypohalitexe2x80x9d) a second liquid includes a gas generating agent, such as a peroxygen containing or releasing agent; and a third liquid includes a reducing agent, such as a thiosulfate compound. At least one of the liquids includes a surfactant. As the liquids are initially separated, each can be maintained in an environment free of reactants and otherwise conducive to their cleaning activity and stability up to the time of use. When the hypohalite and peroxygen compound are allowed to mix, for example, by simultaneously pouring into a drain, they liberate oxygen gas in accordance with the following reaction equation:
NaOCl+H2O2xe2x86x92O2(g)+NaCl+H2O
Moreover the thiosulfate, e.g. sodium thiosulfate reacts with the hypohalite to generate heat. The following equation is illustrative:
4NaOCl+Na2S2O4+2NaOHxe2x86x922Na2SO4+4NaCl+H2O+xcex94H
The liberated gas contacts the surfactant in the solution, creating foam which expands to completely fill the drain pipe. The expanded foam contains an excess of the hypohalite, which acts to clean the drain. The resulting foam is sufficiently stable, a dense to remain in a vertical segment of the pipe to provide active cleaning. In one aspect of the invention, sufficient reactants are provided to yield a foam height sufficient to yield a greater than twelve centimeter column in the drain (as measured from the center or lowest point of the P-trap, and for a 3.2 cm. diameter drain), more preferably greater than seventeen cm. and most preferably seventeen to thirty-one cm. Preferred in terms of foam volume and height in the drain, is an amount sufficient to reach the drain""s stopper mechanism, a site of frequent hair and/or soap contamination. Such stopper mechanisms are typically positioned about twenty cm. up the vertical pipe. The foam would preferably contain greater than 0.1% active, more preferably greater than 0.5% active, and most preferably between about 0.75 and 3% active. An active contact time, or foam half life, should be at least twenty minutes. Foam half-life is the time elapsed between maximum foam volume development and a 50% volume reduction thereof, absent any external forces (other than gravity) acting upon the foam. The foam is self-generating, produced by reaction of composition components, and requires no mechanical agitation or other forms of physical activation. In addition to the foam generated, the reaction between hypohalite and reducing agent generates heat, which is imparted to both the foam and liquid phases. A preferred temperature within the foam is sufficient to insulate the liquid phase from surrounding cold regions, for example at least about 30xc2x0 C. The elevated temperature within the foam may also be sufficient to contribute to the melting of grease in the vertical pipe. A preferred temperature within the liquid phase is sufficient to melt grease, for example 40xc2x0 C. or greater.
In one embodiment of the present invention, at least one of the three liquids includes a thickening agent or system, present in an amount such that when the liquids form an admixture during delivery to a surface, the admixture results in a dense, stable heated foam sufficient for cleaning efficacy and stability. Thus, when the initially separated liquids are allowed to interact, the resulting liquid cleaning composition being delivered to the surface will have the cleaning or bleaching activity and heat delivery appropriate for the cleaning or bleaching of that surface. The term xe2x80x9cliquidxe2x80x9d as used herein may include homogeneous liquids, solutions, suspensions and slurrys. An aqueous liquid is contemplated; however, nonaqueous liquids are within the scope of the invention. The thickening agent or system may impart both a viscous component and an elastic component to the corresponding liquid.
The present invention also relates to a container which maintains the three liquids separately until delivery and provides for such delivery, during which the pH-maintained admixture is formed and delivered to a surface to be treated. The container includes a first compartment for the hypohalite containing liquid, a second compartment for the peroxygen-containing liquid, and a third compartment for the thiosulfate-containing liquid. One, two or all three of the liquids contained therein may contain the thickening system or agent, present in an amount sufficient to thicken and for stability of the liquid, as described above. According to one aspect of the invention, the container may have separate delivery channels for the liquid components for delivering the liquids, whereupon the admixture is formed. These delivery channels may be constructed to provide for the contemporaneous delivery of the liquids to the exterior of the container, whereupon the liquids meet to form the admixture. Alternately, the separate delivery channels may communicate with an admixing space in which the two liquids form the admixture and from which the admixture is delivered to the exterior of the container.
The present invention further includes a method of cleaning surfaces comprising drains which comprises the step of:
pouring into a drain at least one liquid which resolves into a heated liquid phase and a heated foam phase in situ, the foam characterized by a density and stability sufficient to impart cleaning and a temperature of at least 30xc2x0 C. and wherein the foam contains a cleaning-effective amount of a drain cleaning active. The liquid phase provides a temperature of at least about 40xc2x0 C. for cleaning efficiency. It is also within the scope of the present invention to provide a single solution capable of generating the heated foam upon release from its container, as by pouring into the drain.
Briefly, a first embodiment of the present invention comprises a stable cleaning composition comprising, in aqueous solution:
(a) a first liquid containing an oxidizing agent; and
(b) a second liquid containing a gas generating agent;
(c) a third liquid containing a reducing agent and wherein
a first volume of the oxidizing agent and the gas generating agent react to generate a foam characterized by a density and stability sufficient to impart cleaning active, and a second volume of the oxidizing agent and the reducing agent further react to liberate heat, resulting in liquid phase having a temperature of at least about 40xc2x0 C. and a temperature within the foam phase of at least 30xc2x0 C., and wherein the foam contains a cleaning-effective amount of a drain cleaning active.
It should be noted that as used herein the term xe2x80x9ccleaningxe2x80x9d refers generally to a chemical, physical or enzymatic treatment resulting in the reduction or removal of unwanted material, and xe2x80x9ccleaning compositionxe2x80x9d specifically includes drain openers, hard surface cleaners and bleaching compositions. The cleaning composition may consist of a variety of chemically, physically or enzymatically reactive active ingredients, including solvents, acids, bases, oxidants, reducing agents, enzymes, detergents and thioorgainic compounds. Unless otherwise specified, all ingredient percentages are weight percentages.
For purposes of the discussion of the invention disclosed herein, a typical household sink drain comprises four sections: a vertical section, thence to a U-bend (or P-trap), thence to a 90-degree elbow, and finally a horizontal sewer arm.
A viscous rheologoy, preferably one with an elastic component, most preferably a viscoelastic rheology, may be imparted to the oxidant liquid, for example, by a binary surfactant system. One such system includes a betaine or sulfobetaine and an anionic organic counterion. Such systems are more fully described in U.S. Pat. Nos. 4,900,467 and 5,389,157 to Smith, and assigned to the assignee of the invention herein, the disclosures of which are incorporated herein by reference.
The viscosity of the formulations of the present invention can range from slightly greater than that of water, to several thousand centipoise (cP). A preferred viscosity range for the first (oxidant-containing) liquid is about 250 to 2000 cP, alternatively about 500 to 1800 cP, or alternatively about 750-1500 cP. Preferred viscosity for both the second (gag generating) and third (reducing agent) liquids is about 0-50 cP, more preferred is 0-20 cP.
While some viscoelasticity is important to generate a stable, dense durable foam for chemical cleaning efficiency, too high a level of viscoelasticity will result in a reduction in the heat generation. Since the heat generation is optimized at a faster reaction rate, a less viscoelastic formulation will react faster, yielding a heat profile more effective at removing grease clogs. Thus the temperature will be elevated to a sufficient point and for a duration necessary to melt grease.
A second embodiment of the present invention is a composition and method for cleaning drains, the composition comprising separately maintained aqueous solutions of:
(a) a first liquid including a hypohalite compound and having a viscoelastic rheology;
(b) a second liquid including a peroxygen compound; and
(c) a third liquid including a reducing agent.
The liquids (a), (b), and (c) are maintained separately during storage, and combined concurrently with, or immediately prior to use. Preferably, the liquids (a), (b) and (c) are maintained in a triple chamber or compartment bottle, and poured simultaneously into the drain wherein a portion of (a) and (b) react to generate foam, and a portion of (a) and (c) react to liberate heat. The resulting foam is stable and dense, and contains a high percentage of cleaning active, especially hypohalite, which coats the vertical and upper P-trap portions of a drain. The rheology of each composition provides a favorable rate of foam generation and residence time, resulting in excellent cleaning efficacy. The reaction between components (a) and (c) is exothermic, generating sufficient heat to melt grease. The foam should remain stable for an extended period of time, i.e. at least twenty minutes. The viscoelastic rheology may be imparted by a thickener, preferably a surfactant thickener.
It is therefore an advantage of the present invention that the composition is chemically and phase-stable, and retains such stability at both high and low temperatures.
It is another advantage of the present invention that, when formulated as a drain cleaner the composition provides both chemical and physical cleaning, improving the efficacy of the cleaner.
It is another advantage of the present invention that heat is generated, to provide additional physical cleaning efficacy.
It is yet another advantage of the present invention that the composition generates a stable, active-containing foam in-situ.
These and other objects and advantages of the present invention will no doubt become apparent to those skilled in the art after reading the following Detailed Description of the Preferred Embodiments.